Figure 8.

MitoTracker-loaded liposomes target mitochondria of macrophages in mice. (A) Experimental protocol. (1) To observe the mitochondria of resident macrophages, MitoTracker-loaded liposomes were subcutaneously injected into the dorsal side of mice ear pinna one day before in vivo imaging. (2) The LPS was subcutaneously injected into the dorsal side of mice ear pinna to prime inflammation. On the day 3 after LPS injection, MitoTracker-loaded liposomes were subcutaneously injected into the LPS-challenged mice ear. On the day 4 and day 7 after LPS injection, mice were anesthetized for two-photon in vivo imaging. (B) Second harmonic generation (SHG, green) images of collagens and two-photon fluorescence images of mitochondria (red) in c2J mice ear before/after LPS challenge. The excitation wavelength was 1120 nm. Scale bar, 10 µm. (C) 2D scatter plots of mitochondrial organization parameters in macrophages from Matrigel plugs (Naive in vivo, M1 in vivo, M2a in vivo, M2b in vivo, and M2c in vivo) and c2J mice ear (before LPS, 4d after LPS, and 7d after LPS). The quadrants of fission/fusion were added to enclose clustered macrophages in feature space based on their mitochondrial organization. Dots are data of individual cells (n≥10). (D) Second harmonic generation (SHG) images of collagens (blue; excited at 970 nm) and two-photon fluorescence images of macrophage mitochondria (red; excited at 1180 nm) in LysM-Cre\mTmG mice ear before/after LPS challenge. Scale bar, 10 µm. All data shown were representative of two or three independent runs of experiments.